This is the third consecutive year a new global annual temperature record has been set.
All 16 years of the 21century are included in the seventeen warmest years in the modern record (1998 is currently the eighth warmest.)
The five warmest years have all occurred since 2010.
It is increasingly likely the Earth is now warmer than at any time since the Eemian Interglacial, over 115,000 years ago.
The Eemian was warmer than the Holocene because of higher insolation.
Insolation refers to the amount of solar energy received per unit time at any one location, and it was higher due to astronomical cycles.